1. Field of the Invention
The present invention relates to a dielectric rod antenna, which is employed for satellite broadcasting, INMARSAT communication or the like.
2. Description of the Background Art
When a conventional dielectric rod antenna is employed as a primary radiator for a parabolic reflector antenna, gain is disadvantageously caused difference between E-plane radiation pattern and H-plane radiation pattern as received if either one of the dual polarized electromagnetic wave is horizontally polarized and the other one is vertically polarized (this wave is hereinafter referred to as cross-polarized wave), since E-plane radiation pattern and H-plane radiation pattern of the rod antenna have different patterns. When the conventional dielectric rod antenna receives a circularly polarized electromagnetic wave, on the other hand, polarization loss is increased due to the difference in directivity between the E-plane and H-plane radiation patterns. In addition, the antenna efficiency is deteriorated if the antenna has large side lobes.